U.S. patent number 9,937,079 [Application Number 14/080,285] was granted by the patent office on 2018-04-10 for medical drape having an ultra-thin drape film and a thick adhesive coating.
This patent grant is currently assigned to KCI Licensing, Inc.. The grantee listed for this patent is KCI Licensing, Inc.. Invention is credited to Christopher Brian Locke, Timothy Mark Robinson.
United States Patent |
9,937,079 |
Robinson , et al. |
April 10, 2018 |
Medical drape having an ultra-thin drape film and a thick adhesive
coating
Abstract
A system for treating a tissue site includes a pressure source
to apply reduced pressure, and a manifold in fluid communication
with the pressure source to provide reduced pressure to the tissue
site. The system includes a drape for adhering to the tissue site
to cover the tissue site and the manifold. The drape has a film
layer having a thickness less than about 15 microns, and an
adhesive coupled to the film layer. The adhesive seals the film
layer to the tissue site to create a sealed space having the
manifold therein. The adhesive is sufficiently thick to limit leaks
between the film layer and the tissue site.
Inventors: |
Robinson; Timothy Mark
(Basingstoke, GB), Locke; Christopher Brian
(Bournemouth, GB) |
Applicant: |
Name |
City |
State |
Country |
Type |
KCI Licensing, Inc. |
San Antonio |
TX |
US |
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Assignee: |
KCI Licensing, Inc. (San
Antonio, TX)
|
Family
ID: |
49726860 |
Appl.
No.: |
14/080,285 |
Filed: |
November 14, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140188059 A1 |
Jul 3, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61748400 |
Jan 2, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F
13/0289 (20130101); A61F 13/00068 (20130101); A61F
13/0216 (20130101); A61F 13/0233 (20130101); A61F
13/0246 (20130101); A61M 1/90 (20210501) |
Current International
Class: |
A61F
13/02 (20060101); A61F 13/00 (20060101); A61M
27/00 (20060101); A61M 1/00 (20060101) |
References Cited
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Primary Examiner: Marcetich; Adam
Parent Case Text
The present invention claims the benefit, under 35 USC .sctn.
119(e), of the filing of U.S. Provisional Patent Application Ser.
No. 61/748,400, entitled "A Medical Drape having an Ultra-Thin
Drape Film and a Thick Adhesive Coating," filed Jan. 2, 2013, by
Locke et al., which is incorporated herein by reference for all
purposes.
Claims
We claim:
1. A system for treating a tissue site, the system comprising: a
pressure source configured to apply reduced pressure; a manifold
adapted to be in fluid communication with the pressure source to
provide reduced pressure to the tissue site; and a drape
comprising: a film layer having a thickness less than 5 microns, an
adhesive coupled to the film layer and adapted to seal the drape
over the manifold and the tissue site to create a sealed space with
the manifold therein, and the adhesive having a thickness greater
than about 80 microns and less than about 200 microns to limit
leaks between the film layer and the tissue site, wherein the
adhesive is configured to limit leaks through the drape if a
pin-hole opening forms in the film layer.
2. The system of claim 1, wherein the film layer is a
polyurethane.
3. The system of claim 1, wherein the adhesive is a silicone
adhesive.
4. The system of claim 1, wherein the adhesive is an acrylic
adhesive and the film layer is a polyurethane.
5. A dressing for treating a tissue site, the dressing comprising:
a connector adapted to receive reduced pressure from a
reduced-pressure source and apply the reduced pressure to the
tissue site; a manifold adapted to be fluidly coupled to the
connector for receiving the reduced pressure and having a plurality
of flow channels for distributing the reduced pressure to the
tissue site; and a drape the drape including a film layer having a
thickness less than 5 microns and an adhesive coupled to the film
layer and configured to seal the film layer to the tissue site, the
adhesive having a thickness greater than 200 microns and less than
300 microns and a bond strength between about 6N/25 mm and about
10N/25 mm, wherein the adhesive is configured to limit leaks
through the drape if a pin-hole opening forms in the film
layer.
6. The dressing of claim 5, wherein the film layer is a
polyurethane.
7. The dressing of claim 5, wherein the adhesive is a silicone
adhesive.
8. The dressing of claim 5, wherein the adhesive is an acrylic
adhesive.
9. The dressing of claim 5, wherein the adhesive is an acrylic
adhesive and the film layer is a polyurethane.
10. The dressing of claim 5, wherein the adhesive comprises a
hydrocolloid adhesive.
11. The dressing of claim 5, wherein the thickness of the adhesive
at a first portion of the drape is different than the thickness of
the adhesive at a second portion of the drape.
Description
FIELD
The present disclosure relates generally to dressings for adhering
to a patient and, more particularly, but not by way of limitation,
to a medical drape an ultra-thin drape film with a thick adhesive
coating.
BACKGROUND
Clinical studies and practice have shown that providing reduced
pressure in proximity to a tissue site augments and accelerates the
growth of new tissue at the tissue site. The applications of this
phenomenon are numerous, but application of reduced pressure has
been particularly successful in treating wounds. This treatment
(frequently referred to in the medical community as
"negative-pressure therapy," "reduced-pressure therapy," or "vacuum
therapy") provides a number of benefits, which may include faster
healing and increased formulation of granulation tissue. In
applying reduced-pressure therapy, typically a foam pad or other
manifold is placed proximate to the wound, covered with a drape to
form a sealed space, and reduced pressure applied to the sealed
space. If the drape leaks, additional energy may be required to
overcome the leak and maintain the therapeutic level of reduced
pressure.
SUMMARY
These and other problems are generally solved or circumvented, and
technical advantages are generally achieved, by embodiments that
provide a medical drape formed from an ultra-thin drape layer and a
thick adhesive coating.
According to an illustrative, non-limiting embodiment, a system for
treating a tissue site is described. The system includes a pressure
source to apply reduced pressure, and a manifold in fluid
communication with the pressure source to provide reduced pressure
to the tissue site. The system also includes a drape for adhering
to the tissue site to cover the tissue site and the manifold. The
drape has a film layer having a thickness less than about 15
microns, and an adhesive coupled to the film layer. The adhesive
seals the film layer to the tissue site to create a sealed space
having the manifold therein. The adhesive is sufficiently thick to
limit leaks between the film layer and the tissue site.
According to another illustrative embodiment, a dressing for
treating a tissue site is disclosed. The dressing includes a
connector adapted to receive reduced pressure from a source of
reduced pressure and apply the reduced pressure to the tissue site.
The dressing also includes a manifold fluidly coupled to the
connector for receiving the reduced pressure and having a plurality
of flow channels for distributing the reduced pressure to the
tissue site. The dressing further includes a drape including a film
layer having a thickness less than about 15 microns and an adhesive
having a thickness greater than about 80 microns coupled to the
film layer to seal the film layer to the tissue site. The drape is
configured to cover the tissue site and the manifold to provide a
substantially airtight seal that creates a sealed space for the
reduced pressure.
According to yet another illustrative embodiment, a method for
manufacturing a medical drape is described. The method can provide
a film layer having a thickness less than about 15 microns. The
method can also apply an adhesive to the first side of the film
layer. The method may cure the adhesive to form an adhesive on the
first side of the film layer.
According to still another illustrative embodiment, a medical drape
having a film layer and an adhesive coupled to the film layer is
described. The medical drape may be produced by a process
comprising the steps of providing a film layer having a thickness
less than about 15 microns. The process may apply an adhesive to
the first side of the film layer, and cures the adhesive to form an
adhesive on the first side of the film layer.
According to another illustrative embodiment, a medical drape
having a film layer and an adhesive coupled to the film layer is
described. The film layer may have a thickness less than about 15
microns. The adhesive may have a thickness greater than about 80
microns.
Other aspects, features, and advantages of the illustrative
embodiments will become apparent with reference to the drawings and
detailed description that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
Illustrative embodiments are described in detail below with
reference to the attached figures, which are incorporated by
reference herein, and wherein:
FIG. 1 is a schematic, cross-sectional view with a portion shown in
elevation of an illustrative embodiment of a system for treating a
tissue site with reduced pressure;
FIG. 2 is an exploded, perspective view of an illustrative
embodiment of a medical drape of FIG. 1;
FIG. 3 is a cross-sectional view of a portion of the medical drape
of FIG. 2;
FIG. 4A is a detail in cross section of a portion of the system of
FIG. 1 with another medical drape; and
FIG. 4B is a detail in cross section of the portion of the system
of FIG. 4A with the medical drape of FIG. 3.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
New and useful systems, methods, and apparatuses associated with
medical drapes that may be used with reduced-pressure therapy
systems are set forth in the appended claims. Objectives,
advantages, and a preferred mode of making and using the systems,
methods, and apparatuses may be understood best by reference to the
following detailed description in conjunction with the accompanying
drawings. The description provides information that enables a
person skilled in the art to make and use the claimed subject
matter, but may omit certain details already well-known in the art.
Moreover, descriptions of various alternatives using terms such as
"or" do not necessarily require mutual exclusivity unless clearly
required by the context. The claimed subject matter may also
encompass alternative embodiments, variations, and equivalents not
specifically described in detail. The following detailed
description should therefore be taken as illustrative and not
limiting.
FIG. 1 is a schematic diagram of a reduced-pressure therapy system
100 for treating a tissue site 102 illustrating details that may be
associated with some embodiments. The term "tissue site" in this
context broadly refers to a wound or defect located on or within
tissue, including but not limited to, bone tissue, adipose tissue,
muscle tissue, neural tissue, dermal tissue, vascular tissue,
connective tissue, cartilage, tendons, or ligaments. A wound may
include chronic, acute, traumatic, subacute, and dehisced wounds,
partial-thickness burns, ulcers (such as diabetic, pressure, or
venous insufficiency ulcers), flaps, and grafts, for example. The
term "tissue site" may also refer to areas of tissue that are not
necessarily wounded or defective, but are instead areas in which it
may be desirable to add or promote the growth of additional tissue.
For example, negative-pressure therapy may be used in certain
tissue areas to grow additional tissue that may be harvested and
transplanted to another tissue location. The tissue site 102 may be
a wound that extends through an the epidermis 112, through a dermis
116, and into a subcutaneous tissue 118. The tissue site 102 may
include a portion of the epidermis 112 that may be intact and may
surround the tissue site 102. Treatment of the tissue site 102 may
include removal of fluids, for example, exudate or ascites.
The reduced-pressure therapy system 100 may include a drape 106, a
manifold 122, and a connector 128. The drape 106 may have a film
layer 108 and an adhesive layer 110 and be disposed over the
manifold 122 and the portion of the epidermis 112 surrounding the
tissue site 102 to form a sealed therapeutic space 124. The drape
106 may have an aperture permitting fluid communication with the
sealed therapeutic space 124 through the drape 106. The manifold
122 may be disposed within the sealed therapeutic space 124
proximate the tissue site 102. The connector 128 may be coupled to
the drape 106 and be configured to provide fluid communication
through the drape 106 to the sealed therapeutic space 124. The
reduced-pressure therapy system 100 may further include a
reduced-pressure source 126 and a negative-pressure conduit, such
as a tube 130, fluidly coupled to the connector 128.
The manifold 122 may be a substance or structure that may be
provided to apply or distribute reduced pressure to the tissue site
102 and also to remove fluids from the tissue site 102. The
manifold 122 may include a plurality of flow channels or pathways
that can distribute fluids provided to and removed from the tissue
site 102 in response to the application of reduced pressure. In one
illustrative embodiment, the flow channels or pathways may be
interconnected to improve distribution of fluids provided to or
removed from the tissue site 102. The manifold 122 may include a
biocompatible material that is capable of being placed in contact
with the tissue site 102 to distribute reduced pressure to the
tissue site 102. The manifold 122 may also be one or more devices
that have structural elements arranged to form flow channels. In
some illustrative examples, the structural elements may be cellular
foam, open-cell foam, porous tissue collections, liquids, gels, and
other foams that include, or can be cured to include, flow
channels. The manifold 122 may also include porous material, such
as foam, gauze, felted mat, or other material suited to a
particular biological application. The manifold 122 may further
include porous foam that may have a plurality of interconnected
cells or pores that act as flow channels. The porous foam of the
manifold 122 may be a polyurethane, open-cell, reticulated foam
such as GranuFoam.RTM. material manufactured by Kinetic Concepts,
Incorporated of San Antonio, Tex. In other illustrative
embodiments, the manifold 122 may be formed of a bioresorbable
material or a scaffold material. In some situations, the manifold
122 may also be used to distribute fluids such as medications,
anti-bacterials, growth factors, and various solutions to the
tissue site 102.
The reduced-pressure source 126 provides reduced pressure. "Reduced
pressure" generally refers to a pressure less than a local ambient
pressure, such as the ambient pressure in a local environment
external to a sealed therapeutic environment provided by the sealed
therapeutic space 124. In many cases, the local ambient pressure
may also be the atmospheric pressure at which a patient is located.
Alternatively, the pressure may be less than a hydrostatic pressure
associated with tissue at the tissue site. Unless otherwise
indicated, values of pressure stated herein are gauge pressures.
Similarly, references to increases in reduced pressure typically
refer to a decrease in absolute pressure, while decreases in
reduced pressure typically refer to an increase in absolute
pressure.
The fluid mechanics of using a negative-pressure source to reduce
pressure in another component or location, such as within a sealed
therapeutic environment, can be mathematically complex. However,
the basic principles of fluid mechanics applicable to
reduced-pressure therapy are generally well-known to those skilled
in the art, and the process of reducing pressure may be described
illustratively herein as "delivering," "distributing," or
"generating" reduced pressure, for example.
The reduced-pressure source 126 may be a suitable device for
supplying reduced pressure, such as a vacuum pump, wall suction,
micro-pump, or other source. In an illustrative embodiment, the
reduced-pressure source 126 may be an electrically-driven vacuum
pump. In another illustrative embodiment, the reduced-pressure
source 126 may be a manually-actuated or manually-charged pump that
does not require electrical power. Reduced pressure may also be
generated by a device, for example, a micro-pump, directly coupled
to the drape 106. The reduced-pressure source 126 may be other
types of reduced-pressure pumps, or may be a wall suction port such
as those available in hospitals and other medical facilities. While
the amount and nature of reduced pressure applied to the tissue
site 102 may vary according to the application, reduced pressure
may be between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa), and
more typically between -75 mm Hg (-9.9 kPa) and -200 mm Hg (-26.66
kPa).
In general, components of the reduced-pressure therapy system 100
may be coupled directly or indirectly. For example, the
reduced-pressure source 126 may be directly coupled to the
connector 128 and indirectly coupled to the manifold 122 through
the connector 128. Components may be fluidly coupled to each other
to provide a path for transferring fluids (i.e., liquid and/or gas)
between the components. The connector 128 may also have a port to
receive the tube 130 for fluid coupling between the tube 130 and
the connector 128. In one illustrative embodiment, the connector
128 may be a T.R.A.C..RTM. Pad or Sensa Pad available from KCI of
San Antonio, Tex. The connector 128 may allow reduced pressure to
be delivered to the sealed therapeutic space 124. In other
illustrative embodiments, the connector 128 may also be a conduit
inserted through the drape 106.
A "tube," as used herein, broadly refers to a tube, pipe, hose,
conduit, or other structure with one or more lumina adapted to
convey fluids between two ends. Typically, a tube may be an
elongated, cylindrical structure with some flexibility, but the
geometry and rigidity may vary. In some embodiments, components may
additionally or alternatively be coupled by virtue of physical
proximity, being integral to a single structure, or being formed
from the same piece of material. Coupling may also include
mechanical, pneumatic, thermal, electrical, or chemical coupling
(such as a chemical bond) in some contexts. For example, the tube
130 may be a multi-lumen conduit having a primary lumen and a
secondary lumen. In an illustrative embodiment, the tube 130 may
supply reduced pressure through the primary lumen and may sense
pressure through the secondary lumen. The tube 130 may have a
variety of shapes and include multiple primary and secondary
lumens. The tube 130 may fluidly communicate with the sealed
therapeutic space 124 through the connector 128 to supply the
sealed therapeutic space 124 with reduced pressure and sense
pressure at the tissue site 102. Reduced pressure developed by the
reduced-pressure source 126 may be delivered through the tube 130
to the connector 128.
In general, exudates and other fluids flow toward lower pressure
along a fluid path, a phenomenon often referred to as "suction" or
"vacuum." This orientation may be generally presumed for purposes
of describing various features and components of reduced-pressure
therapy systems herein. Thus, the term "downstream" typically
implies something in a fluid path relatively closer to a
negative-pressure source, and conversely, the term "upstream"
implies something relatively further away from a negative-pressure
source. Similarly, it may be convenient to describe certain
features in terms of fluid "inlet" or "outlet" in such a frame of
reference. However, the fluid path may also be reversed in some
applications (such as by substituting a positive-pressure source
for a negative-pressure source) and this descriptive convention
should not be construed as a limiting convention.
In general, negative-pressure therapy can be beneficial for wounds
of all severity, but the cost and complexity of negative-pressure
therapy systems often limit the application of reduced-pressure
therapy to large, highly-exudating wounds present on patients
undergoing acute or chronic care, as well as other severe wounds
that are not readily susceptible to healing without application of
reduced pressure. For example, the complexity of conventional
negative-pressure therapy systems can limit the ability of a person
with little or no specialized knowledge from administering
negative-pressure therapy.
Often, the effectiveness of negative-pressure therapy may be
limited due to the inability of the drape 106 to conform to the
tissue site 102 while still providing a seal between the drape 106
and the epidermis 112. Polyurethane films may often be used to form
the film layer 108 of the drape 106 due to polyurethane's ability
to be breathable, flexible, robust, printed or colored, and
provided in a range of thicknesses. Polyurethane film layers also
bond well to most adhesives. The challenges for using polyurethane
films in medical drape applications is to balance between
conformability, adhesion, sealing, breathability, robustness, and
cost. Currently, most medical drapes have film layers with a
thickness ranging from at least 15 microns to about 50 microns.
Such medical drapes may be manufactured by starting with a
polyurethane film layer having a thickness of about 5 microns. A
polyurethane film having a thickness of about 5 microns may not be
considered a medical grade material. Typically, a polyurethane film
having a thickness of about 5 microns may be used as an
intermediary stage of the manufacturing process. The polyurethane
film layer may be further coated with other polyurethane solutions
to achieve a final thickness of 15 microns or more. The 5 micron
film layer is not currently available for medical applications for
a variety of reasons that will be discussed below, but only used in
the manufacturing process.
The medical drape functions to enclose and protect the wound,
maintain a moist environment within the wound, act as a barrier to
infectious agents, and provide a seal, particularly where
reduced-pressure therapy is being utilized. When low-leak or
no-leak reduced-pressure therapies are used, the ability of the
medical drape to seal the tissue site and maintain the reduced
pressure at a desired level becomes more critical. In order to
improve sealing of a medical drape, a thicker adhesive may be
required. The adhesive, commonly acrylic-based, may have a coating
coverage between about 15 g/m.sup.2 (gsm) up to about 65 gsm which
equates to a coating thickness ranging between about 15 microns and
about 65 microns for medical applications. It is understood that
the thicker adhesives, that is, adhesives having a thickness closer
to about 65 microns, combined with a polyurethane film layer having
a standard thickness of 15 microns or more to form a medical drape
may be useful for such low-leak or no-leak reduced-pressure
applications.
However, medical drapes having a thicker adhesive layer may have an
increased size and an increased structural complexity that may give
rise to increased manufacturing costs. Medical drapes having a
thicker adhesive may also negatively effect conformability and
breathability. To overcome these problems, a medical drape may have
a thinner polyurethane film layer. For example, a polyurethane film
layer approximately 10 microns or less may be used. However,
polyurethane films having a thickness of approximately 10 microns
or less may be prone to stretching, creasing or wrinkling, and
tearing during manufacturing. The creases or wrinkles may create
leakage problems. For example, FIG. 4A is a sectional view of a
drape 206 illustrating additional details of a medical drape having
a thinner polyurethane film layer and thicker than standard
adhesive layer. The drape 206 may be formed from a polyurethane the
film layer 208 having a thickness of greater than about 15 microns
and an the adhesive 210 less than about 80 microns is shown. When
the drape 206 is positioned at the tissue site 102 over the
manifold 112, a crease 244 is formed leaving a gap 245 because the
adhesive 210 is too thin to seal the gap 245.
Efforts to use thinner polyurethane films less than about 15
microns have also not resolved the problems because such film
layers, especially those having a thickness of about 5 microns, may
be susceptible to the risk of pin-holing defects. Pin-holing is the
forming of microscopic openings or tears in the flexible film that
may cause the film layer, and consequently the medical drape, to
fail. In addition, the polyurethane film thickness must be
maintained to aid in handling of the medical drape as thinner
polyurethane films may make the medical drape more difficult to
apply. It is also known that some adhesives, such as acrylic
adhesives, significantly reduce the moisture vapor transmission
rate (MVTR) of a medical drape as the adhesive layer increases in
thickness. Because of these problems, polyurethane film layers
having a thickness of 5 microns have not been available for medical
drape applications especially for low-leak or no-leak applications
of reduced-pressure therapy. Because of the unavailability of such
thin film layer polyurethane, the adhesive layer has remained
relatively thin, between approximately 15 microns and approximately
65 microns, to maintain an acceptable MVTR.
As disclosed herein, system 100 overcomes these challenges and
others by providing a drape 106 having a thinner the film layer 108
and a thicker the adhesive 110. In addition, the drape 106 may
provide a thicker adhesive without compromising breathability or
conformability. Still further, the drape 106 having a thinner film
layer may be less susceptible to pin-holing defects.
FIG. 2 is an exploded perspective view of the drape 106
illustrating additional details that may be associated with some
embodiments. The drape 106 may include the film layer 108 and the
adhesive layer 110. The adhesive 110 may be configured to be
positioned adjacent to the film layer 108. The film layer 108 may
have a first side 132 and a second side 134. The first side 132 may
be configured to be non-tacky so that the first side 132 may not
generally adhere to objects placed in contact with the first side
132. The film layer 108 may also be configured to be an exterior or
upper portion of the drape 106 so that the first side 132 may be
exposed to the ambient environment when positioned at the tissue
site 102. The adhesive 110 may have a first side 136 configured to
be coupled to the film layer 108 and a second side 138 configured
to be coupled to the epidermis 112. The adhesive 110 may be a
material that both bonds and seals the film layer 108 of the drape
106 to a portion of the epidermis 112 surrounding the tissue site
102 whereby the drape 106 forms sealed space 124 when disposed over
the tissue site 102.
The drape 106 substantially prevents the leakage of fluids, for
example, through the space between the drape 106 and the tissue
site 102, while allowing vapor to egress through the drape 106. The
drape 106 may maintain a suitable MVTR where the adhesive 110
contacts the epidermis 112 to aid in healing of the tissue site 102
and limit maceration of the epidermis 112 to which the drape 106 is
sealed. The drape 106 may also maintain sealing contact with the
epidermis 112 surrounding the tissue site 102 when the
reduced-pressure therapy is applied to the tissue site 102. The
drape 106 also may be formed from a material that is suitably
releasable from the epidermis 112 to minimize or reduce pain to the
patient resulting from the removal of the drape 106 from the tissue
site 102. While the drape 106 may be releasable, the drape 106
maintains an adequately strong mechanical connection to the tissue
site 102 as a function of the bonding characteristics of the
adhesive 110.
The film layer 108 may be a flexible film that may be breathable
and typically may have a high moisture-vapor-transfer-rate (MVTR).
The film layer 108 may be formed from a range of medically approved
films ranging in thickness of less than about 5 microns. The film
layer 108 may comprise a suitable material or materials, such as
the following: hydrophilic polyurethane (PU), cellulosics,
hydrophilic polyamides, polyvinyl alcohol, polyvinyl pyrrolidone,
hydrophilic acrylics, hydrophilic silicone elastomers, and
copolymers of these. The high MVTR of the film layer 108 allows
vapor to egress and inhibits liquids from exiting. In an
illustrative embodiment, the film layer 108 may also function as a
barrier to liquids and microorganisms.
The adhesive 110 may be a medically-acceptable, pressure-sensitive
adhesive. In an illustrative embodiment, the adhesive 110 may be a
high bond strength acrylic adhesive, high-tack silicone adhesive,
polyurethane, or other substance. In some embodiments, the bond
strength of the adhesive 110 may have a peel adhesion or resistance
to being peeled from a stainless steel material between about 6N/25
mm to about 10N/25 mm on stainless steel substrate at 23.degree. C.
at 50% relative humidity based on the American Society for Testing
and Materials ("ASTM") standard ASTM D3330. In an illustrative
embodiment, the adhesive 110 comprises an acrylic adhesive with a
coating weight between about 80 gsm and about 400 gsm. A coating
weight between about 80 gsm and about 400 gsm may correspond to a
thickness of about 80 microns to about 400 microns. In other
embodiments, the adhesive 110 may be a silicone adhesive with a
coating weight of up to 600 gsm. In still other embodiments, the
adhesive 110 may be a hydrocolloid adhesive having a coating weight
of up to 1000 gsm.
The drape 106 having the adhesive 110 may be manufactured using a
hot melt manufacturing system. The drape 106 may also be
manufactured using a manufacturing process that does not use a
solvent coating system as currently known in the art. Hot melt
manufacturing systems melt the adhesive of the adhesive 110 so that
the adhesive becomes less viscous. The melted adhesive may then be
applied to the film layer 108 and cooled to form the adhesive 110.
In an illustrative embodiment, a film layer having a thickness less
than about 15 microns may be provided. The acrylic adhesive of the
adhesive 110 may be heated up to about 120.degree. C. to melt the
acrylic adhesive of the adhesive 110. Other adhesives may be heated
to higher or lower temperatures to achieve a suitable viscosity for
application of the particular adhesive to the film layer 108. The
melted adhesive may be applied to the film layer 108 and cured to
form the adhesive 110. In an illustrative embodiment, the melted
adhesive may be coated onto the film layer 108 and cooled to form
the adhesive 110. The drape 106 may also be manufactured in an
extrusion process to pattern coat the film layer 108 with the
adhesive 110 so that the adhesive 110 may have different
thicknesses at different portions of the drape 106.
The drape 106 may be susceptible to fewer instances of pin-holing
than expected when limiting the film layer 108 to a thickness of
less than 15 microns. The increased thickness of the adhesive 110
may decrease the instances of pin-holing by filling the pin-holes
that form in the film layer 108. In addition, the overall
breathability of the drape 106 may be increased over other medical
drapes because of the improved MVTR of the film layer 108.
Increasing the thickness of the adhesive of the adhesive 110 may
decrease the MVTR of the adhesive 110, but reducing the thickness
of the film layer 108 increases the MVTR of the film layer 108 to
balance out the lower MVTR of the adhesive 110. Pairing the
adhesive 110 with the film layer 108 may cause an increase in the
overall MVTR of the drape 106 or at least maintain the overall MVTR
at an acceptable level, aiding in maintenance of healthy the
epidermis 112 adjacent the tissue site 102.
As described above, FIG. 4A is a cross sectional view of a portion
of system 100 of FIG. 1 using a common medical the drape 206 having
a film layer 208 between about 25 microns and about 45 microns and
an the adhesive 210. When medical the drape 206 is applied to the
tissue site 102, medical the drape 206 may be stretched to conform
medical the drape 206 to the tissue site 102 and ensure that
medical the drape 206 seals to the intact the epidermis 112
surrounding the tissue site 102. When the force stretching medical
the drape 206 during application is released, medical the drape 206
may contract, causing wrinkle or the crease 244 to form where
medical the drape 206 is coupled to the epidermis 112. The crease
244 pulls both the film layer 208 and the adhesive 210 away from
the epidermis 112, and due to the thickness of the film layer 208,
the adhesive 210 is not sufficiently strong or thick enough to
close the gap between medical the drape 206 and the epidermis 112.
Thus, the crease 244 causes leaks that reduce the efficiency of
system 100.
FIG. 4B is a cross sectional view of a portion of system 100 of
FIG. 1 illustrating additional details of the drape 106 that may be
associated with some embodiments. The drape 106 may be less than
about 15 microns, but still include wrinkle or the crease 144. The
crease 144 may cause a portion of the drape 106 to be pulled away
from the epidermis 112 as described above. However, because the
adhesive 110 may be thicker, between about 80 microns and 400
microns, the adhesive 110 may not pull away from the epidermis 112
to form a gap 145 as shown by the dashed line. The adhesive 110 may
fill the entire void under the crease 144, preventing a leak. The
adhesive 110 may fill the openings between the film layer 108 and
the epidermis 112, thereby limiting the formation of leaks that may
prevent proper operation of system 100. Thus, the drape 106,
substantially prevents leakage of fluid through the space between
the drape 106 and the tissue site 102, while maintaining a high
MVTR and increased conformability.
In other embodiments, the adhesives may be mixed with blowing or
expanding agents, for example organic and inorganic low temperature
boiling point liquids. The blowing or expanding agents allow for
the adhesives to expand under the application of heat or light to
increase the thickness of the adhesive following deposition by one
of the above described processes. The blowing or expanding agents
may reduce the amount of adhesive needed and decrease the cost of
production and the cost of the resulting medical drape. In some
embodiments, the application of heat or light may be delayed until
application of the medical drape to the epidermis so that the
contact area with the epidermis increases as the adhesive may be
warmed by contact with the epidermis. The application of light or
heat following application of the medical drape to the epidermis
may provide a better seal of the medical drape to the epidermis
while retaining strong bonding characteristics.
The medical drapes and their equivalents as described above may be
thinner than standard drapes, may have high MVTRs, and may be
highly conformable. In addition, they may have reduced instances of
leaks due to their increase adhesive thickness. Still further the
medical drapes and their equivalents described herein may have a
lower production cost. The medical drapes and their equivalents
herein may also be subject to simpler application and high
breathability.
Although the certain embodiments and their advantages have been
disclosed in the context of certain illustrative, non-limiting
embodiments, it should be understood that various changes,
substitutions, permutations, and alterations can be made without
departing from the scope of the invention as defined by the
appended claims. It will be appreciated that features that may be
described in connection to one embodiment may also be applicable to
other embodiments. It will also be understood that the benefits and
advantages described above may relate to one embodiment or may
relate to several embodiments. It will further be understood that
reference to "an" item refers to one or more of those items.
The steps of the methods described herein may be carried out in a
suitable order, or simultaneously where appropriate and as
otherwise understood by one skilled in the art.
Where appropriate, aspects of the embodiments described above may
be combined with aspects of the other embodiments described to form
further examples having comparable or different properties and
addressing the same or different problems.
It will be understood that the embodiments described herein are
given by way of example only and that various modifications may be
made by those skilled in the art. The above specification, examples
and data provide a complete description of the structure and use of
exemplary embodiments. Although various embodiments have been
described above with a certain degree of particularity, or with
reference to one or more individual illustrations, those skilled in
the art could make numerous alterations to the example embodiments
without departing from the scope of the claims.
* * * * *